Abstract: In recent years, with the development of tumor molecular biology technology, molecular targeted therapy has become a study hotspot, which plays a significant role on breast cancer treatment strategy. Among them, the human epidermal growth factor receptor2 (Her2) has been proven as an effective molecular target. So molecular targeted therapy of breast cancer become another important treatment except chemotherapy and endocrine therapy.

Key words: Breast neoplasms, Targeted therapy, Her2 gene